TJP chat in the lounge wrote:(6:27:32 AM) phreadom: ただいま～ (6:28:33 AM) Relye: Why does no one put the 'su' at the end?

And since I really couldn't give a good answer without basically guessing (by trying to explain the difference between "tada ima" and "tada imasu")... I figured it was better to ask here and see if I (we) could get a more accurate, succint, and education answer.